EF1 tornado in St. Tammany Parish, Louisiana

NWS ground survey confirmed an EF-1 tornado with maximum sustained winds of 105 mph. The tornado began near or before moving into Treasure Isle where it flipped a large boat on its side. Additional visible damage to homes and lofting of outdoor fixtures was noted as the tornado moved into Martin Drive. The tornado reached EF-1 intensity near Bluegill Drive where it removed shingles off of homes, snapped a few trees, and collapsed garage door structures and blew out a wall or two as a result in two different homes. A defined damage path was observed on LA Hwy 433 and then crossed into inaccesible marsh areas. A weak tornado debris signature was evident on KHDC and is the basis for connecting this damage to Avery Estates. The tornado continued northeast into Avery Estates where minor metal roof damage and tree damage was noted on Avery Drive and Smokey Hollow Drive. The tornado evidently strengthened and grew in size to around 300 yards in width as it moved just south of the northern part of Avery Drive and into US Hwy 190 where numerous trees were uprooted or snapped. Several outbuildings were damaged and tension cables on a cell tower were snapped. It's possible the tornado slowed in this area as it pivoted and turned more to the east per KHDC radar imagery. Along US Hwy 190 a manufactured home had most of its roof removed and it was shifted significantly off its foundation. The tornado then moved into Pearl River Basin, inaccessible to ground survey. The tornado evidently maintained strength or even strengthened further over this area, evidenced by the deepening of a tornado debris signature lofted over 5000 feet. The tornado exited St. Tammany Parish, entering Hancock County in Mississippi north of the town of Pearlington.

A mesoscale convective system formed on the eastern side of Post-Tropical Storm Arthur on June 18th. Favorable low level winds allowed for multiple mini-supercells to form on the leading edge of the mesoscale convective system resulting in several tornadoes impacting the Houma and New Orleans metro areas. These tornadoes were rated as EF-0 and EF-1 events. Additionally, the mesoscale convective complex tapped into a region of deep tropical moisture with atmospheric moisture content well above normal levels for mid-June. This resulted in several significant flash flooding events in portions of the Houma and New Orleans metro areas including the cities of Houma, Kenner, and Slidell. Another area of heavy rainfall from thunderstorms formed over central Louisiana near the center of Post-Tropical Storm Arthur producing flash flooding in portions of Pointe Coupee Parish. Lingering moisture and weak upper level troughing associated with the slow moving remnants of Post-Tropical Storm Arthur produced additional thunderstorm activity on June 19th. This activity was focused in metro New Orleans where a brief EF-0 tornado developed in the community of Arabi. On June 20th, another band of thunderstorms developed along a lingering boundary stretching from coastal Louisiana toward New Orleans. This band of thunderstorms produced heavy rainfall and impacted portions of the Houma and New Orleans metro areas producing a few flash flooding events in Houma, Destrehan, and Kenner.